Process of working up pit coal



Patented Mar. 25, 1941 UNITED STATES PATENT OFFICE PROCESS OF WORKING UP PIT COAL Franz Herglotz, Karlsbad, Czechoslovakia.

No Drawing. Application August 31, 1939, Serial No. 292,839. In Germany September 7, 1938 Claims.

I grinding operation.

I have now discovered that a material particularly suitable for mouldinginto briquettes and the like without the aid of binders can be produced by moistening the coal before the fine comminution, (that is to say by increasing its water content) and then drying it again.

Based on the foregoing discovery, the present invention provides a process of working up coal for briquetting Without the aid of binders, which comprises preliminarily moistening said coal and thereupon drying it again.

In carrying out the invention, the drying of the moistened pit coal can take place before or during the fine comminution of else partly before and partly during the fine comminution. The moistening can be effected directly or indirectly, for example by spraying water through nozzles on to the coal or by treating the coal with steam to deposit the condensing Water thereon.

The aforedescribed steam treatment of the coal produces a rise in temperature of the coal which has a particularly favourable eifect both on the grinding and on the briquettes produced. It has been found that the pit coal gains in mouldability through the moistening and re-drying, in such a way that not only is the moulding facilitated but the moulded products obtained are also firmer and have a glossy surface of better appearance than was hitherto possible when briquetting without binders. The invention also enables defective mouldings, especially so-called splitters to be avoided.

The moulding of the pit coal pretreated in accordance with the invention can be carried out in any moulding or briquetting press customary for such purposes, but with particular advantage in ring-roller moulding presses.

The invention will hereinafter be illustrated by the following examples:

Example I A lean coal containing 1.05% of moisture, 55 6.60% of ash and 12.65% of volatile constituents is preliminarily crushed in a hammer mill, whereupon water is sprayed thereon through nozzles until it is completely saturated with water. The wet coal is then rapidly dried in a drum dryer down to a water content of about 1%. The thus treated coal is then finely ground and transferred directly into a briquetting press without any admixture of binder and is there converted into high grade briquettes.

Example II A bituminous coal containing 0.76% of moisture, 4.4% of ash and 23.76% of volatiles is coarsely comminuted and then treated with steam. The steam condenses on the pieces of coal and moistens the latter. Due to the heat liberated in the condensation of the steam the coal becomes Warm. The warm moist coal is then transferred to a ball mill, wherein it is finely ground. During the grinding operation there are passed through the ball mill hot waste gases of a suificiently high CO2 content to prevent explosion. By virtue of this, the water deposited on the coal is evaporated and led off with the waste gases so that the coal is dried down to approximately its initial moisture content. The dry hot finely ground coal is transferred by the waste gases into dust collectors and led directly from thence while still in a hot state, into a ring-roller moulding press without the addition of any binder. black briquettes of high mechanical strength are thus obtained.

I claim:

1. A process of producing briquette from pit coal, which comprises preliminarily moistening said pit coal, drying and finely comminuting said moistened pit coal and thereupon cold pressing said coal to form a briquette without the addition of an extraneous binder.

2. A process of producing briquette from pit coal, which comprises preliminarily moistening said pit coal, finely comminuting and simultaneously drying said moistened pit coal and thereupon cold pressing said coal to form a briquette without the addition of an extraneous binder.

3. A process of producing briquette from pit coal, which comprises preliminarily subjecting said pit coal to a treatment with steam for the purpose of moistening and warming the same, drying and finely comminuting said moistened pit coal and thereupon cold pressing said coal to form a briquette without the addition of an extraneous binder. i

4. A process of producing briquette from pit coal, which comprises preliminarily coarsely com- Glossy minuting said pit coal, moistening said coarsely comminuted pit coal, drying and finely comminuting said moistened coarsely comminuted pit coal and thereupon cold pressing said coal to form a briquette without the addition of an extraneous binder.

5. A process of producing briquette from pit coal, which comprises preliminarily coarsely com- 

